First, set the association on a machine, export it using command with elevated CMD:

dism.exe /online /export-defaultappassociations:c:\tmp\defaultassociations.xml

Copy this to a shared folder //your_fileserver/share/defaultassociations.xml

Second, Deploy this file to each computer for better stability:

Open GPO management console, Create a new GPO and navigate to Under Computer Configuration> Preferences > Windows Settings > Files, create a new rule with “//your_fileserver/share/defaultassociations.xml” as source path, “C:\Windows\System32\defaultassociations.xml)” as target path.

Third, In this same GPO, navigate to Computer Configuration > Policies >Administrative Templates > Windows Components > File Explorer, double click the Set a default associations configuration file. Select Enabled, then under default associations configuration file  type: “c:\windows\system32\defaultassociations.xml

 

Link this GPO to your computer OU, done !